Memory swivel for swivel chair



May 28, 1968 F. DOERNER MEMORY SWIVEL FOR SWIVEL CHAIR Filed Sept. 28,1966 l la Ill TL J INVENTOK FMNK DOEMEK ATTORNEY United States Patent3,385,550 MEMORY SWIVEL FOR SWIVEL CHAIR Frank Doemer, Waterloo,Ontario, Canada, assignor to Doerner Products Co., Limited, Waterloo,Ontario, Canada, a corporation of Canada Filed Sept. 28, 1966, Ser. No.582,746 1 Claim. (Cl. 248-417) ABSTRACT OF THE DISCLOSURE A memoryswivel for a chair having an upper and lower sleeve like cams mounted onthe chair spindle, the upper sleeve being fixed against rotation and thelower sleeve secured to the spindle by a pin which extends into anenlarged slot formed in a tubular control member fixed to a supportpost. The lower sleeve rotates with the spindle with the rotationlimited 'by the pin to about 90 in either direction from the centeredposition. When the spindle is under load the cams are out of contact.

Background of inventiom This invention relates to what is commonly knownas a memory swivel for a swivel chair; that is to a swivel which isconstructed and arranged so that it will have a centered position andwill automatically return to that position whenever the chair isswivelled in either direction from such centered position.

This invention relates to that type of memory swivel which comprises abase member having a tubular fixed post, a chair spindle mounted in saidpost for rotative movement therein, spring means resiliently supportingsaid spindle for longitudinal up and down movement, a pair of sleevesmounted on said spindle in end-to-end relationship within said post, oneof said sleeves being secured to the post and the other being secured tosaid spindle, said sleeves having on their contiguous ends, spiral camfaces which are complemental to each other and when brought intoengagement by said spring biasing means will react to return the spindleto a predetermined centered position.

When a load is applied to the spindle it moves downwardly separating thetwo cams which permits the spindle to freely swivel about itslongitudinal axis in either direction from the centered position. One ofthe problems experienced with the type of memory swivel heretofore inuse, is that slamming of the cams takes place when the spindle isrotated from the centered position. This results from the fact that thecrests of the cams form a stop to limit the swivelling of the spindle ineither direction from a centered position. This constant slamming of thecams results in breakage and damage due to the cam pressure.

Description of invention An object of this invention is to provide amember for restricting the rotation of the spindle to less than 90 ineither direction from the centered position and thus eliminate theslamming action heretofore present in the memory swivels presently inuse.

The present invention is accomplished by a memory swivel for a swivelchair comprising, in combination, a base member having an uprighttubular fixed post in which is mounted a tubular control, a chairspindle mounted in said tubular control for rotative and longitudinalmovement therein, spring mean resiliently supporting said spindle, upperand lower sleeves mounted in endto-en'd relationship within said tubularcont-r01, the upper sleeve being secured to the tubular control, and apin extending diametrically through the spindle and the lower sleevethereby securing it to the spindle to be movable therewith, said sleeveshaving on their opposed contiguous ends plate cams normally out ofengagement when said spindle is under load and cooperating to returnsaid spindle to a centered position when said spindle is not under loadand an enlarged slot in the tubular control in registration with lowersleeve an an extension on the pin projecting into the slot, therebylimiting the rot-ative movement of the spindle to about in eitherdirection from the centered position without interferring with the freeup and down movement of the spindle and without injurious pressures onthe cams.

For an understanding of the invention and its construction and operationreference is to be made to the following description which isillustrated by the accompanying drawings.

In the drawings;

FIGURE 1 illustrates a memory swivel, partly in cross-section,constructed in accordance with the present invention.

'FIGURE 2 is a view, partly in cross-section, with the spindle underload with the cam faces out of contact and the spindle rotated out ofits centered position.

.FIGURE 3 is a cross-sectional view on the line 33 of FIGURE 2.

FIGURE 4 is a view, partly in cross-section, of a memory swilvelconstructed according to the prior art, .to illustrate the constructionheretofore in use.

Referring now to the drawings, I have shown only such parts of theswivel chair as are necessary for the explanation of the presentinvention.

The swivel chair comprises a base 10, a seat III, a seat support member12, a tubular post 13, which is secured to and supported by the base inan upright position, a tubular control 14, which fits inside the post 13with a slide fit and is secured against rotating therein by a pin 15.

The memory swivel of the present invention which is illustrated inFIGURES 1, 2 and 3 of the drawings, comprises a spindle 16 mountedwithin the tubular control 14 and has mounted on its top end, the seatsupport member 12. The lower end of the spindle .16 is journaled in thelower end of the tubular casing '14 by a conventional ball race 17. Theupper end of the spindle .16 is journaled in the casing by means of aupper sleeve 18- which is secured against longitudinal and rotativemovement therein by the pin 1 5 and a set screw 19. A lower sleeve 20 ismounted on the spindle below the upper sleeve 18, the lower sleeve 20being pinned to the spindle by means of pin 21 whereby the spindle andsleeve 20 move together. The pin 21 is extended so as to project througha rectangular slot formed in the tubular control 14, the width of theslot being arranged and proportioned to permit up and down movement ofthe spindle and the length being such that it permits the spindle tohave limited rotative movement on either side of a centered positionwhich will be described later. A compression spring 23 surrounds thespindle I16 and is captured between the ball race 17 and the secondsleeve 20. The compression spring 23 resiliently supports the spindle'16 which reacts as weight is applied to and removed from the seat 11.

The contiguous ends of the upper and lower sleeves 18, 20 are eachrespectively formed with oomplernental upper and lower plate cams whichare constructed and arranged to return the spindle to a centeredposition as hereinafter described. The lower plate cams on the end ofthe lower sleeve 20 are of semi spiral form and are indicated by thenumerals 2'4, 25. The contiguous end of .the upper sleeve 18 is formedwith similar upper cam plates indicated by the numerals 26, 27. Thesecam plates nest together with their faces abutting in the centeredposition, and react to return the spindle to the centered positionwhenever the spindle is rotated from that position and the applied forceis removed from the seat. The rotative movement of the spindle in eitherdirection for the centered position is limited by the pin 21. Thecircumferential length of the slot 22 is such that the pin 21, servingas a stop, stops the rotation of the spindle before the cams can slamtogether.

It will be seen from the foregoing that as soon as a weight is appliedto the seat 11, the spindle will move downwardly separating the platecams. The seat 11 can then be swivelled in either direction from acentered position, the pin 21 limiting the swivelling action in thepresent illustration to less than 90 in either direction from thatcentered position. The cams, as shown in FIGURE 2, are then out ofcontact, in which position the tips of the lower cam plates are at thehalf way position between the highest and lowest point of the upper cam.If a person who is sitting on the seat, swivels the seat from thecentered position and then rises from the seat, the compression spring23 will react to bring the cam plates together which cooperate to returnthe spindle to its centered position.

Referring now to FIGURE 4, which illustrates the structure presently inuse, the parts which correspond to similar parts described andillustrated in conjunction with FIGURES 1 to 3 have been given the samenumerals. :In this construction, the downward movement of the spindle isarrested by the thrust Washer 25. The crests of the cams form the stopfor limiting the rotation of the spindle with constant slamming of thesurfaces.

What I claim as new and desire to protect by Letters Patent of theUnited States is:

1. A memory swivel for a swivel chair comprising, in combination, a basemember having an upright tubular fixed post in which is mounted atubular control, a chair spindle mounted in said tubular control forrotative and longitudinal movement therein, spring means resilientlysupporting said spindle, upper and lower sleeves mounted in end-to-endrelationship within said tubular control, the upper sleeve being securedto the tubular control, and a pin extending diametrically through thespindle and the lower sleeve thereby securing it to the spindle to bemovable therewith, said sleeves having on their opposed contiguous endsplate cams norm-ally out of engagement when said spindle is under loadand cooperating to re turn said spindle to a centered position when saidspindle is not under load and an enlarged slot in the tubular control inregistration with lower sleeve and an extension on the pin projectinginto the slot, thereby limiting the rotative movement of the spindle toabout 90 in either direction from the centered position withoutinterferring with the tree up and down movement of the spindle andwithout injurious pressures on the cams.

References Cited UNITED STATES PATENTS 1,895,226 1/1933 Kupski 248-4171,897,676 2/1933 Ries 248417 2,691,407 10/1954 Kupski 248417 FRANCIS K.ZUGEL, Primary Examiner.

